/* main.c */
#include <stdlib.h>
#include <stdio.h>
#include "factorial.h"

int main(int argc, char **argv) {
    int n, result;
    if (argc != 2) {
        fprintf(stderr, "usage: factorial n, n >=0\n");
        return 1;    
    }    
    n = atoi(argv[1]);
    result = factorial(n);
    printf("factorial %d!=%d\n", n, result);
    return 0;
}
